There is no way you will get to the Poly in time. The Fantasmic show is about 30 minutes long. Then depending upon where you are sitting (how far over and how far down), it can take you another 20 minutes just to get out to Hollywood Boulevard. From there, you have to either catch a bus (which will be packed) or take the tram out to your car. Then you still have to get out of the parking lot. It is only a 10-15 drive to the Poly, but if you are on the bus, you will stop at either the WL or the Contemporary before the Poly.